Kinesis Advantage MPC, with the recessed keys. Here's a picture of me with the keyboard: http://www.railsonmaui.com/about/

It's very important that the keyboard is low enough so your wrists are straight. In other words, avoid putting it on top of a high desk.

I've been using this keyboard since working with Richard Williamson and Paul King at Infoscape in in 1997. It does take some getting used to, and you might want to configure the location of some of the keys. I have all the mac modifier keys accessible to my thumbs on BOTH sides so that I hit the modifier with one hand and use the opposite hand for the key, almost always.

Here's a link on Amazon: http://smile.amazon.com/Kinesis-KB500USB-BLK-Advantage-Conto...